chore: remove stories/checker backend dead code

Remove the dead stories/checker backend tracked as design debt in CLAUDE.md:
- Delete internal/api/stories.go, stories_test.go, elaborate.go
- Delete internal/task/story.go, story_test.go
- Remove story/checker columns from storage schema and all CRUD methods
- Remove checkStoryCompletion, spawnCheckerTask, triggerStoryDeploy,
  createValidationTask, checkValidationResult, ShipStory, CheckStoryCompletion
  from executor; simplify handleRunResult
- Remove story/checker fields from task.Task (StoryID, AcceptanceCriteria,
  CheckerForTaskID, CheckerReport)
- Remove story routes and geminiBinPath from API server
- Move claudeJSONResult/extractJSON from elaborate.go to validate.go
- Rename ensureStoryBranch -> ensureBranch in ContainerRunner
- Fix git identity in bare-repo tests; fix initial-branch to use main

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/internal/api/validate.go b/internal/api/validate.go
index 07d293c..9e91882 100644
--- a/internal/api/validate.go
+++ b/internal/api/validate.go
@@ -7,11 +7,29 @@ import (
 	"fmt"
 	"net/http"
 	"os/exec"
+	"strings"
 	"time"
 )
 
 const validateTimeout = 20 * time.Second
 
+// claudeJSONResult is the top-level object returned by `claude --output-format json`.
+type claudeJSONResult struct {
+	Result  string `json:"result"`
+	IsError bool   `json:"is_error"`
+}
+
+// extractJSON returns the first top-level JSON object found in s, stripping
+// surrounding prose or markdown code fences the model may have added.
+func extractJSON(s string) string {
+	start := strings.Index(s, "{")
+	end := strings.LastIndex(s, "}")
+	if start == -1 || end == -1 || end < start {
+		return s
+	}
+	return s[start : end+1]
+}
+
 const validateSystemPrompt = `You are a task instruction reviewer for Claudomator, an AI task runner that executes tasks by running Claude or Gemini as a subprocess.
 
 Analyze the given task name and instructions for clarity and completeness.